Isolation Shelter Pressurized to Avoid Transfer of Contaminants Between an Isolation Space and the Outside Environment

ABSTRACT

An isolation shelter includes, in its interior, an inner closure defining an isolation space. The isolation space is at a pressure less than the pressure of the environment in the shelter interior, at the outside of the inner enclosure. An outer enclosure of the shelter encloses a sealed region defined at least in part by a structural element contained within the shelter interior A sealed space, which is partially defined by any portion of the outer enclosure that can become exposed to the environment outside the outer enclosure, extends from the outer enclosure into the shelter interior. The sealed space is at a pressure exceeding the pressure of the environment outside of the shelter, thereby substantially preventing contamination in the environment outside the shelter from entering the shelter interior and passing to the isolation space. The pressure in the isolation space substantially prevents contaminants from escaping the isolation space into the environment outside the isolation shelter.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 60/732,843 filed Nov. 2, 2006, assigned to the assignee of this application and incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates generally to an isolation shelter or a clean room containing an isolation space and, more particularly, pressurizing an isolation shelter or a clean room containing an isolation space to prevent, or substantially prevent, escape of contaminants from the isolation space to the external environment and entry of contaminants from the external environment into the isolation space.

BACKGROUND OF THE INVENTION

In the post 9/11 world, there is an increased awareness of the potential of a bioterrorist attack, and also naturally occurring biological or chemical events, that would require the isolation and quarantine of a large number of casualties. The SARS episode, during which two hospitals in Toronto, Canada, became SARS-only facilities that denied medical services to the general public, showed that current healthcare facilities are not prepared to handle a large surge of infectious patients. A potentially imminent viral flu epidemic would require the isolation and treatment of a large population of infectious patients, which could outstrip current healthcare capabilities.

To meet these new threats, the healthcare community needs to have the capability to isolate a large number of patients, and to quarantine a large number of suspected infected patients, to prevent the spread of the disease. The current WHO estimate is that a pandemic, such as may be associated with the avian flu, could result in millions of deaths unless adequate quarantine, isolation and treatment are available. The civilian healthcare community cannot function with the large number of infectious patients that could occur during a bioterrorist attack, such as smallpox, or a natural pandemic, such as avian flu.

An isolation shelter, which may be in the form of a building, room, tent or other like structure and defines an enclosed space, is typically used by the healthcare community to isolate patients. The enclosed space of the shelter, for example, can be maintained at a pressure exceeding the pressure outside the shelter (“positive pressure”), such as by supplying more HEPA and/or charcoal filtered air into the shelter than the air being vented or leaking from the shelter. The positive pressure prevents or substantially prevents airborne toxic contaminates or vapors in the external environment from entering the shelter. Thus, civilians within the enclosed space of an isolation shelter are isolated from any toxic vapor or biological/radiological particulate contamination existing outside of the shelter.

To protect the general population from infectious patients who, for example, may spread disease by coughing or sneezing, infected patients are isolated in the enclosed space of an isolation shelter which is maintained at a pressure that is less than the pressure of the outside environment (“negative pressure”). The negative pressure prevents or substantially prevents any airborne biological contaminate within the shelter from escaping to the external environment. Negative pressure is typically created by removing more air from the enclosed space than is supplied to and/or leaks into the enclosed space. To assist in infection control, the air within a negative pressure shelter may be filtered with a HEPA filter having, for example, a filtration efficiency of 99.99% for >0.3 micron particles at a rate of at least 12 air exchanges per hour.

Therefore, there is a need for an isolation shelter that prevents or substantially prevents contaminants in the environment outside of the shelter from entering an enclosed space defined within the shelter and, in turn, contaminating people or objects contained within the enclosed space; and that prevents or substantially prevents airborne contaminants generated by infectious patients or objects contained within the enclosed space from escaping the shelter into the external environment and, in turn, contaminating the environment outside the shelter.

SUMMARY OF THE INVENTION

In accordance with the present invention, an isolation shelter includes an inner enclosure defining an isolation space, and an outer enclosure enclosing a sealed region defined at least in part by a structural element contained within the interior of the shelter. A sealed space, which is partially defined by any portion of the outer enclosure that can become exposed to the environment outside the outer enclosure, in other words, the environment outside the shelter, extends from the outer enclosure into the interior or sealed region of the shelter. A portion of the inner enclosure may also define the sealed space. The sealed space is at a pressure exceeding the pressure of the environment outside of the shelter, or at a positive pressure. The positive pressure in the sealed space prevents or substantially prevents contamination in the environment outside the shelter from entering through the outer enclosure into the sealed space, and then passing from the sealed space into the isolation space directly, or indirectly via an enclosed space(s) disposed intermediate the sealed space and the isolation space. The isolation space is at a pressure less than the pressure of the environment of the interior of the shelter outside the inner enclosure, in other words, at a negative pressure in relation to the sealed space or an intermediate enclosed space at the outside of the inner enclosure. The negative pressure within the isolation space prevents or substantially prevents contaminants from escaping the isolation space, and then passing through the sealed space, or through an intermediate enclosed space and then the sealed space, to the environment outside the isolation shelter.

Preferably, an air blower system including tubing coupled to the sealed space and the isolation space maintains the sealed space and the isolation space under the desired positive and negative pressures, respectively. The air blower system preferably filters any air supplied to the isolation shelter, and also filters any air exiting the isolation shelter before its release to the external environment.

In a preferred embodiment, the isolation shelter includes an entry/egress port in a portion of each of an outer wall of the outer enclosure and an inner wall of the inner enclosure. In still a further preferred embodiment, an air lock system having re-closable ports, for example, doors, at opposing ends constitutes the entry/egress port at an outer wall of the outer enclosure, and one of the re-closable ports opens into the sealed space and the other of the re-closable ports opens into the environment outside of the isolation shelter. In an alternative preferred embodiment, an air lock system extends between an entry/egress port in an outer wall of the outer enclosure and an entry/egress port in an inner wall of the inner enclosure, and the opposing re-closable ports, respectively, open to the environment outside of the isolation shelter and within the isolation space. The air lock system preferably is maintained at a positive pressure and filters the air contained within, and most preferably is at a pressure slightly less than the pressure outside of the shelter.

In a preferred embodiment of the present invention, an isolation shelter includes outer walls sealed to each other and a floor to define an outer enclosure, and inner walls sealed to each other and the same floor to define an inner enclosure contained within the outer enclosure. The region defined between the outer enclosure and the inner enclosure is a sealed, wall space, and the region defined within the inner enclosure is an isolation space. The wall space is maintained under positive pressure in relation to the environment at the outside of the outer enclosure, in other words, outside of the shelter, and the isolation space is maintained under negative pressure in relation to the pressure within the wall space. An air blower system coupled to the wall space and the isolation space maintains the respective spaces under the desired positive and negative pressures, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the present invention will be apparent from the following detailed description of the presently preferred embodiments, which description should be considered in conjunction with the accompanying drawings in which like references indicate similar elements and in which:

FIG. 1A is perspective view of an embodiment of an isolation shelter in accordance with the present invention.

FIG. 1B is a cross-sectional view of the shelter of FIG. 1A taken along line 1B-1B in FIG. 1A.

FIG. 1C is a cross-sectional view of the shelter of FIG. 1A taken along line 1C-1C in FIG. 1A.

FIG. 2 shows an embodiment of the isolation shelter of FIG. 1A in cross-sectional view, as in FIG. 1B, and coupled to an air blower system in accordance with the present invention.

FIG. 3A is perspective view of another embodiment of an isolation shelter in accordance with the present invention.

FIG. 3B is a cross-sectional view of the shelter of FIG. 3A taken along line 3B-3B in FIG. 3A.

FIG. 4 is a cross-sectional view of another embodiment of an isolation shelter in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

For purposes of highlighting the features of the present invention, an isolation shelter pressurized to prevent or substantially prevent (i) atmospheric contamination in the environment outside the shelter from entering an isolation space within the shelter, and (ii) airborne contaminants within the isolation space from escaping the isolation shelter into the outside environment, is described in detail below in connection with an isolation shelter whose outside environment is the atmosphere of the earth. It is to be understood that the features of the inventive isolation shelter are similarly applicable to portable containers, clean rooms or other enclosed spaces whose outside environment may be other than the earth's atmosphere.

FIG. 1A is a perspective view of an exemplary embodiment of an isolation shelter 10, in accordance with the present invention, whose outside environment is the earth's atmosphere. Referring to FIG. 1A, and also to FIG. 1B, which shows a cross-sectional view of the shelter 10, the shelter 10 includes five outer walls 12 including four lateral outer walls 12A and an outer ceiling 12B; four inner walls 14 including four lateral inner walls 14A and an inner ceiling 14B, and a floor 16. The four walls 12A are sealed to each other at adjacent lateral edges, to the ceiling 12B at their top edges and to the floor 16 at their bottom edges to form a box-shaped outer enclosure or container 18 enclosing a space 19. In a preferred embodiment, the container 18 is an integral unit which includes all of the walls 12 and the seals between the edges of the walls 12. Similarly, the four walls 14A are sealed to each other at adjacent lateral edges, to the ceiling 14B at their top edges, and to a portion of the floor 16 at their bottom edges to form a box-shaped inner enclosure or container 20 enclosing a space 21. In a preferred embodiment, the container 20 is an integral unit which includes all of the walls 14 and the seals between the edges of the walls 14.

Referring to FIG. 1A, the container 20 is disposed within the sealed interior region of space 19 enclosed by the container 18. Although the containers 18 and 20 share the same floor 16 in the illustrated embodiment of the shelter 10, the shelter 10 may be constructed in accordance with the present invention where the flooring to which the walls 12A are sealed is an independent flooring which is not a part of the flooring to which the bottom edges of the walls 14B are sealed, and which may or may not be sealed to the flooring to which the walls 14B are sealed.

In another alternative embodiment, the containers 18 and 20 share wall components. For example, a portion of the ceiling forming the container 18 can be the ceiling from which the container 20 is formed.

Each of the walls 12 and 14 is preferably made of material that is impermeable, or substantially impermeable, to substantially all liquids, solids, such as particulates, and gases, such as air, and can include polymeric material, steel, plaster, or other well known building materials. In addition, the floor 16, like the walls 12 and 14, is preferably made of material impermeable, or substantially impermeable, to substantially all liquids, solids and gases. Further, the seals between the walls, and the walls and the floor, in the shelter 10 are seals that are preferably impermeable, or substantially impermeable, to substantially all liquids, solids and gases. Consequently, a sealed wall space 26 is defined between the container 18 and the container 20, and the space or isolation space 21 enclosed by the container 20 is also a sealed space.

The impermeable seals at all connections of walls to each other or to the floor for each of the containers 18 and 20 prevent unwanted leakage of, for example, contaminants, into and out of the spaces 21 and 26 of the shelter 10.

In accordance with the present invention, any portion of an outer wall of the outer container 18 that can become exposed to the environment outside of the outer container 18 defines the sealed wall space 26. Referring to FIG. 1A, it is assumed that the earth's atmosphere, which is at an ambient pressure, surrounds all portions of the outer container 18, except for the floor 16, such that the earth's atmosphere outside the shelter is the environment outside the walls 12 of the outer container 18. As the floor 16 is not exposed to the external atmosphere, all five walls 12 of the container 18 are exposed to the outside environment and, therefore, define the wall space 26. In addition, in the shelter 10, the five walls 14 and the portion of the floor 16 extending between the walls 12A and 14A also define the wall space 26. The wall space 26 is at a pressure exceeding the pressure of the environment at the outside of the container 18, or at a positive pressure. Also according to the present invention, the isolation space 21 is at a pressure less than the pressure of the environment of the interior of the shelter 10 outside the inner container 20. In the illustrated embodiment of the shelter 10 the wall space 26 is the environment at the outside of the container 20.

In a preferred embodiment, air, which is preferably HEPA and/or charcoal filtered air, is supplied into the wall space 26 to create and maintain positive air pressure in the wall space 26. If the shelter 10 includes doors, windows, or wall cracks in the outer walls 12 through which the pressurized air may leak from the wall space 26 into the environment outside the shelter 10, air is continuously replenished to the wall space 26 to maintain a positive pressure in the space 26.

In addition, in a preferred embodiment, air, which is also preferably HEPA and/or charcoal filtered air, is supplied into the isolation space 21 and air is also exhausted from the space 21. Typically, more air is exhausted from the isolation space 21 than returned to the space 21, so as to maintain a negative pressure in the isolation space 21. The maintenance of positive pressure in the wall space 26 and negative pressure in the isolation space 21 using an air blower system 80 is discussed in detail below in connection with the text accompanying the description of FIG. 2.

Referring again to FIG. 1A, the shelter 10 includes entry/egress ports 30 and 32 defined in one or more of the inner and outer walls 12 and 14, respectively. The entry/egress ports 30 and 32, for example, can constitute sealed portals through which tubing from an air blower system extends into the shelter 10 and terminates within the spaces 21 or 26. Alternatively, a port can constitute or be a part of an air lock system. An air lock system, when used in connection with the shelter 10, provides that individuals can enter and leave the isolation shelter 10 without disrupting the pressurization of the spaces 21 and 26 and, thus, avoids contaminants in the environment outside the shelter 10 from entering the space 26 and contaminants from escaping the space 26 into the environment outside the shelter 10. The use of an air lock system in connection with the shelter 10 is discussed in detail below in connection with text accompanying the description of FIG. 1C.

FIG. 2 is a schematic, functional block diagram illustration of exemplary interconnections between an air blower system 80 and the spaces 21 and 26 of the isolation shelter 10, and where the blower system 80 operates to maintain positive air pressure in the wall space 26 and negative air pressure in the isolation space 21, in accordance with the present invention. Referring to FIG. 2, an air entry pipe 72 extends from within the isolation space 21, through an opening 32A in one of the inner walls 14A, through the wall space 26 and then exits the shelter 10 through an opening 30A in one of the outer walls 12A. In addition, an air exit pipe 74 extends from within the isolation space 21, through an opening 32B in one of the inner walls 14A, through the wall space 26 and then exits the shelter 10 through an opening 30B in one of the outer walls 12A. Further, an air entry pipe 76 extends from outside the shelter 10, through an opening 30C in one of the outer walls 12A and terminates in the wall space 26.

Still referring to FIG. 2, the blower system 80, which preferably includes the pipes 72, 74 and 76, includes an inlet port 82, an air intake port 84, outlet ports 86 and 88, and ducts 90, 92 and 94 which are coupled to and extend from the ports 88, 82 and 86, respectively. The ducts 90 and 92 are coupled at their open ends to the pipes 72 and 74 at the ports 30A and 30B, respectively, of the shelter 10. Further, the duct 94 is coupled to the port 30C, and optionally includes an overpressure valve 96 that can open to the environment external to the duct 94, such as the earth's atmosphere.

In operation, the blower system 80 supplies air, which may be processed by decontamination, HEPA filtration and/or charcoal filtration within the system 80, to the isolation space 21 via the port 88, the duct 90 and the pipe 72. In addition, the blower system 80 draws air from the isolation space 21 via the pipe 74, the duct 92 and the inlet port 82. Also, the blower system 80 supplies some of the air returned at the inlet port 82 to the wall space 26 via the outlet port 86, the duct 94 and the port 30C.

The blower system 80 supplies a sufficient amount of air to the outlet port 86 to maintain positive air pressure within the wall space 26. The valve 96 within the duct 94 controls the amount of air supplied to the wall space 26 and, thus, the pressure of the air within the wall space 26. If there is essentially no leakage in the wall space 26, substantially all of the air supplied to the duct 94 will exit through the valve 96. If there is leakage in the wall space 26, such as through an entry/egress port 30, or a wall crack, then little or no air will exit the duct 94 through the valve 96 and most of the air that the blower system 80 supplies to the duct 94 will enter the wall space 26 to maintain the desired positive pressure.

In an alternative embodiment, the valve 96 is omitted from the blower system 80 and the blower system 80, instead, includes a pressure sensor 89 coupled to the duct 94. The sensor 89 determines the pressure within the space 26 by monitoring the pressure in the duct 94 at the outlet port 86, and suitably regulates the volume of air the blower system 80 supplies at the outlet 86 to maintain a desired level of positive pressure within the space 26. The blower 80 draws fresh air from the environment, as needed, through the intake vent 84 for use in the supply of preferably filtered air to the space 26 to maintain positive pressure therein.

As discussed above, some of the air drawn from the isolation space 21 exits the blower 80 at the outlet 86, such that the withdrawn air is not returned to the isolation space 21. The blower system 80 creates and maintains negative pressure in the isolation space 21 by providing that the amount of air withdrawn from the space 21 exceeds the amount of air supplied to the space 21.

In a preferred embodiment, the blower system 80 includes conventional pressure sensors 91 and 93 at the inlet 82 and the outlet 88, respectively, which monitor the flow of air through the ports 82 and 88. In a further embodiment, the sensors 91 and 93 act as regulators that open and close the individual ports 82 and 88 to maintain a negative pressure in the isolation space 26. Alternatively, the sensors 91 and 93 provide data representative of the pressure in the isolation space 26 to a conventional controller (not shown) within the blower system 80. The controller controls the volume of air supplied to the port 88, with or without opening or closing the port 88, and also controls the opening and closing of the port 82, to maintain a desired pressure in the isolation space. In another embodiment, one or more of the sensors 89, 91 and 93 are located within the spaces 21 and 26 and can communicate pressure data to the controller in the blower system 80 via wires (not shown), or wirelessly.

The blower system 80 can be any conventional air blowing system operable, in connection with the isolation shelter 10, to supply filtered air at the outlet 86 to create and maintain positive pressure in the space 26; to supply a sufficient amount of filtered air at the outlet 88, in relation to the amount of the air received at the inlet 82 from the space 21, to create and maintain negative pressure at the isolation space 21; and to receive air at the inlet 84, as necessary, for use in supplying filtered air at the outlet 86 to maintain positive pressure in the space 26 and, optionally, for use in supplying air at the outlet 88 as needed.

It is to be understood that commercial blowers and filtration devices may be readily adapted for use in the blower system 80 to supply air from two outlets, as well as to provide the air flows needed to create the desired positive and negative pressures in the isolation shelter 10. In a preferred embodiment, the blower system 80, for example, includes a HEPA and/or a charcoal filter coupled to the air stream of a blower that supplies air to the ports 86 and 88. In another preferred embodiment, the blower system 80 is part of an air decontamination device, such as that disclosed in U.S. patent application Ser. No. 10/434,041, filed on May 8, 2003 and published as U.S. Patent Publication No. U.S. Patent Publication No. 2004/0146437 Al on Jul. 29, 2004, or part of an air decontamination, heating, ventilation, and air conditioning device (“ADHVAC”), which is described in U.S. patent application Ser. No. 11/089,795, which was filed on Mar. 3, 2005 and was published as U.S. Patent Publication No. 2005/0211415 Al on Sep. 29, 2005, each of which is incorporated by reference herein.

In a preferred embodiment, the air in the wall space 26 is maintained at a positive pressure that meets the military Collective Protection requirement of 0.5 inches water column over pressure, and the isolation space 26 is maintained at a negative pressure of at least 0.01 inches water column less than the ambient air pressure outside the shelter 10.

Referring to FIGS. 1A and 1C, in a further embodiment of the present invention, a pressurized airlock entry/egress system 130A extends from within the space 21, through a port 32F in an inner wall 14A and a port 30F in an outer wall 12A, and to the outside environment. In addition, a pressurized airlock entry/egress system 130B extends from the space 26, through a port 32G in an inner wall 14A and to the outside environment. Further, a pressurized airlock entry/egress system 130C (not shown) extends from within the space 21, through a port 32G in an inner wall 14A and into the space 26. Each of the systems 130 is a conventional air lock system, as well known in the art, which provides for passage of an individual between respective ends. For example, the system 130A constitutes a sealed passageway having doors that can be opened into the space 21 and the outside environment. In a preferred embodiment, each of systems 130 is maintained at a pressure exceeding ambient pressure of the outside environment and less than the positive pressure in the wall space 26. In a further preferred embodiment, each of the systems 130 filters air within the passageway and requires a waiting interval between the opening and closing of one door and the opening and closing of the opposing door.

In another embodiment, both doors of the passageway of the system 130A or 130B can be opened at once, although such implementation is not very desirable because the chances for transfer of contaminants between the isolation space 21 and the outside environment, in either direction, increases.

In a preferred implementation of the shelter 10, the isolation space 26 is occupied by a patient. By maintaining a negative pressure in the isolation space 21, the filtered air maintains a proper oxygen level and reduces CO₂ buildup to enable safe human occupation of the space 26. The shelter 10, thus, provides that CDC guidelines for airborne infection isolation or protective isolation can be maintained through use of a suitable blower system in connection with the shelter 10. The air within the isolation space 21 can be recirculated through a HEPA filter to generate the desired air exchanges per hour (12 air changes per hour (“ACH”) for isolation and 15 ACH for surgery) for the removal of infectious patient-generated airborne contaminates. The recirculating air would also be environmentally controlled to maintain a comfortable living space (temperature and humidity) in the space 21, independent of the ambient outside environment. The negative pressure of >0.01 water column can be controlled by the filtered exhaust air flow.

FIG. 3A is a perspective view of another exemplary embodiment of an isolation shelter 110, in accordance with the present invention. Like reference numerals are used to describe elements in the shelter 110 identical or similar in construction and operation to the elements in the shelter 10 described above. Referring to FIG. 3A, and also to FIG. 3B, which shows a cross-sectional view of the shelter 110, the shelter 110 includes an outer enclosure 112 including three outer walls 12A, a ceiling 12B, a shared wall 102A and a portion of a floor 16. The three walls 12A are arranged with respect to one another as three consecutively attached lateral walls of a rectangularly-shaped container or outer enclosure 112, sealed to each other at adjacent lateral edges, to the ceiling 12B at their top edges and to the floor 16 at their bottom edges. The shared wall 102A forms the fourth lateral wall of the rectangular outer enclosure 112, is sealed to the lateral edges of the adjacent walls 12A, to the ceiling at its top edge and to the floor 16 at its bottom edge. The walls 12A, 102A and the corresponding floor portion 16 form the outer enclosure 112 that encloses a sealed wall space 26. In a preferred embodiment, the container 112 is an integral unit which includes all of the walls 12 and the seals between the edges of the walls 12.

Still referring to FIGS. 3A and 3B, the wall 102A that forms the container 112 is one of four walls 102A that are arranged with respect to one another as the lateral walls of a rectangularly-shaped container 120. The container 120 includes the four walls 102A sealed to each other at adjacent lateral edges, to a ceiling 102B at their top edges and to another portion of the floor 16 at their bottom edges. The container 120 is formed from the walls 102 and the floor portion 16 to which the walls 102A are sealed. In a preferred embodiment, the container 120 is an integral unit which includes all of the walls 102 and the seals between the edges of the walls 102.

The container 120 of the shelter 110 contains an inner container 20 enclosing an isolation space 21. The inner enclosure 20 includes four lateral inner walls 14A, of which one wall 14A constitutes a portion of one of the walls 102. As in the shelter 10, the walls 14, an inner wall ceiling 14B and a portion of the floor 16 to which the walls 14A are sealed forms the isolation space 26. An intermediate, sealed space 126, thus, is defined between the inner container 20 and the container 120.

In the embodiment of the shelter 110 illustrated in FIGS. 3A and 3B, it is assumed that all of the walls 102, except for the wall 102A forming a portion of the enclosure 112, and all portions of the floor 16 would not come into contact with the outside environment. For example, the shelter 110 is within a cave where all of the walls 102, except for the wall 102A forming a portion of the enclosure 112, and all portions of the floor 16 are embedded within the cave, such that the outside environment would not contact any of these structures. Consequently, in the shelter 110 only the space 26 needs to be maintained at a pressure exceeding the pressure of the outside environment. The isolation space 21 is at a pressure less than the pressure in the space 126, as the space 126 constitutes the environment outside the container 20. The pressure in the space 126 can be at any desired pressure, so long as the pressure within the space 21 can be maintained at less than the pressure in the space 126. For example, the space 126 can constitute a passageway or a working area in the shelter 110 maintained at ambient conditions.

Referring to FIG. 3B, an air lock system 130H extends between a port 130H located in the sole wall 12A that can come in contact with the outside environment, and a port 132H in the intermediate wall 102A defining the container 112, such that the air lock system 130H defines a passageway between the space 126 and the outside environment. In addition, an air lock system 130J extends through a port 32H in a wall 14A and defines a passageway between the space 126 and the isolation space 21.

In operation of the shelter 110, the positive pressure in the space 26 prevents or substantially prevents contaminants at the outside of the wall 12A of the shelter 110 from entering the space 126 and, ultimately, passing into the isolation space 21. In addition, the negative pressure in the space 21 prevents or substantially prevents contaminants in the space 21 from entering the space 126 via leaks or cracks in any of the walls 14, which partially define the space 126 and, thus, are in contact with the environment of the space 126. Thus, the negative pressure in the space 21 provides that contaminants in the space 21 would not escape into the space 126, pass from the space 126 through the wall 102A that defines the enclosure 112, then through the space 26 and into the outside environment.

In a preferred embodiment, the inventive isolation shelter includes a solid wall enclosure, such as a room, within a fixed structure, such as a building, or an ISO-container or other solid wall portable enclosure.

FIG. 4 is a cross-sectional view of an isolation shelter 150, in accordance with the present invention, for use in an existing soft fabric or hard wall enclosure or shelter facility 160. The shelter 150 has a construction functionally similar to the construction of the shelter 10, as shown in FIG. 1A, and like components are referred to below using the same reference numerals as used to describe the shelter 10. Referring to FIG. 4, the shelter 150 includes a loose fitting, double walled balloon type polymer liner having an outer liner 152 and an inner liner 154. The outer liner 152 is anchored or attached to several locations, including at corners, of inner surfaces of walls 162A and a ceiling 162B of the facility 160, via conventional tie downs 164. A sealed wall space 26 is defined between the liners 112 and 114. The liners 112 and 114 preferably are heat sealed to a floor 16 to form the sealed containers 18 and 20 defining the spaces 26 and 21.

The liners 112 and 114 preferably are made of fabric or other suitable material having the above-described solid, liquid and gas impermeability qualities. The outer liner 112 may be constructed of a chemical warfare (CW) or Toxic Industrial Chemical (TIC) impermeable material, such as those used by and being developed by the U.S. Army, for example, for collective protection shelters. The inner liner 114 could be made of material similar to the outer wall 112 material, or alternatively could be a flexible polymer material, such as polyethylene, etc. Either or both of the liners 112 and 114 could be fabric. In addition, the edges of the liners 112 and 114 adjacent to the floor 16 are sealed to the floor 16 by a heat seal also having the above-described solid, liquid and gas impermeability qualities.

In a preferred embodiment, the soft fabric shelter 150 is supported in a facility 160 that is in the form of a frame, such as a tent, or an air beam structure.

Although preferred embodiments of the present invention have been described and illustrated, it will be apparent to those skilled in the art that various modifications may be made without departing from the principles of the invention. 

1. An isolation shelter having an interior region, the shelter comprising: an inner enclosure defining an isolation space; and an outer enclosure defined at least in part by a first structural element contained within the interior region of the shelter, wherein any portion of the outer enclosure that can become exposed to an environment outside the outer enclosure defines at least a portion of a sealed wall space, wherein the wall space extends from the outer enclosure into the interior region and is at a pressure exceeding the pressure of the environment at the outside of the outer enclosure, and wherein the isolation space is at a pressure less than the pressure of the environment of the interior region of the shelter outside the inner enclosure.
 2. The isolation shelter of claim 1, wherein at least a portion of the inner enclosure defines at least a portion of the wall space.
 3. The isolation shelter of claim 1, wherein the pressure in the wall space substantially prevents contamination in the environment outside the shelter from entering through the outer enclosure, into the wall space, and then passing from the wall space into the isolation space.
 4. The isolation shelter of claim 1, wherein the first structural element is a wail of the inner enclosure.
 5. The isolation shelter of claim 1, wherein the first structural element is not a part of the inner enclosure and defines a portion of an intermediate space, wherein the intermediate space is further defined by at least portion of the inner enclosure.
 6. The isolation shelter of claim 5, wherein the pressure in the wall space substantially prevents contamination in the environment outside the shelter from entering through the outer enclosure into the wall space, passing from the wall space into the intermediate space, and then passing from the intermediate space, through the inner enclosure and into the isolation space.
 7. The isolation shelter of claim 1, wherein the pressure within the isolation space substantially prevents contaminants from escaping the isolation space, passing through the inner enclosure into the wall space, and then passing from the wall space through the outer enclosure and into the outside environment.
 8. The isolation shelter of claim 5, wherein the pressure within the isolation space substantially prevents contaminants from escaping the isolation space, passing through the inner enclosure into the intermediate space, passing from the intermediate space into the wall space, and then passing from the wall space through the outer enclosure and into the outside environment.
 9. The isolation shelter of claim 1, wherein a portion of at least one of an outer wall of the outer enclosure and an inner wall of the inner enclosure includes an entry/egress port.
 10. The isolation shelter of claim 1, wherein a portion of each of an outer wall of the outer enclosure and an inner wall of the inner enclosure includes at least one entry/egress port.
 11. The isolation shelter of claim 10, wherein the outer enclosure includes a first port and the inner enclosure includes second and third ports, wherein a desired pressure is maintained in the isolation space by supplying more air at the second port than withdrawn at the third port and wherein a desired pressure is maintained in the wall space by supplying air at the first port.
 12. The isolation shelter of claim 10, wherein the air supplied at the first and second ports is at least one of particulate filtered, charcoal filtered and decontaminated air.
 13. The isolation shelter of claim 10, wherein the air withdrawn at the third port is at least one of particulate filtered, charcoal filtered and decontaminated
 14. The isolation shelter of claim 10, wherein any portion of the air withdrawn at the third port is at least one of particulate filtered, charcoal filtered and decontaminated before release to the outside environment.
 15. The isolation shelter of claim 10, wherein the amount of air supplied at the first port is regulated by at least one of an air pressure sensor coupled to an air conduit extending into the first port and a pressure regulation valve within the air conduit.
 16. The isolation shelter of claim 10, wherein the amount of air being supplied at the second port and withdrawn at the third port are regulated, such that a desired pressure is maintained in the isolation space.
 17. The isolation shelter of claim 1, wherein a portion of an outer wall of the outer enclosure and an inner wall of the inner enclosure includes first and second entry/egress port, respectively, and wherein an air lock passageway extends between the first and second ports.
 18. The isolation shelter of claim 1, wherein at least one of a portion of an outer wall of the outer enclosure and an inner wall of the inner enclosure includes an entry/egress port and wherein an air lock passageway constitutes the port.
 19. The isolation shelter of claim 1, wherein the first structural element is not a part of the inner enclosure and includes an entry/egress port and wherein an air lock passageway constitutes the port.
 20. The isolation shelter of claim 1, wherein the outer enclosure and the inner enclosure is substantially impermeable to substantially all liquids, solids and gases.
 21. The isolation shelter of claim 20, wherein at least one of the outer enclosure and the inner enclosure includes at least one of flexible polymeric material, steel and plaster.
 22. The isolation shelter of claim 1, wherein at least a portion of at least one of the outer enclosure and the inner enclosure is an integral unit.
 23. The isolation shelter of claim 1, wherein the outer enclosure and inner enclosure define the wall space.
 24. An air blower system for coupling to an isolation shelter, wherein the isolation shelter comprises: an inner enclosure defining an isolation space; an outer enclosure defined at least in part by a first structural element contained within the interior region of the shelter, wherein any portion of the outer enclosure that can become exposed to an environment outside the outer enclosure defines at least a portion of a sealed wall space, wherein the wall space extends from the outer enclosure into the interior region and is at a pressure exceeding the pressure of the environment at the outside of the outer enclosure and wherein the isolation space is at a pressure less than the pressure of the environment of the interior region at the outside of the inner enclosure; and wherein the outer enclosure includes a first port and the inner enclosure includes second and third ports; the blower system comprising: first, second and third ducts coupled to the first, second and third ports, respectively, wherein air is supplied to the wall space and the isolation space, respectively, through the first and second ducts and wherein air is withdrawn from the isolation space through the third duct; an inlet for receiving outside air; and a first means for regulating the amount of air being supplied to the wall space, such that a desired pressure is maintained in the wall space.
 25. The blower system of claim 24, wherein the first means is a pressure regulating valve included in the first duct or a pressure sensor coupled to the first duct.
 26. The blower system of claim 24, wherein the air supplied at the first and second ports is at least one of particulate filtered, charcoal filtered and decontaminated air.
 27. The blower system of claim 24, wherein the air withdrawn at the third port is at least one of particulate filtered, charcoal filtered and decontaminated.
 28. The blower system of claim 24, wherein any portion of the air withdrawn at the third port is at least one of particulate filtered, charcoal filtered and decontaminated before release to the outside environment.
 29. The blower system of claim 24 further comprising: a second means for regulating the amount of air being supplied to and withdrawn from the isolation space, such that a desired pressure is maintained in the isolation space.
 30. The blower system of claim 29, wherein the amount of air being supplied to the second port exceeds the amount of air being withdrawn at the third port.
 31. The blower system of claim 24, wherein the air received at the inlet is at least one of particulate filtered, charcoal filtered and decontaminated.
 32. A method of isolating an isolation space within an isolation shelter comprising: at any portion of the shelter that can become exposed to an environment outside the shelter, maintaining a pressure exceeding the pressure of the environment outside the shelter; and maintaining an isolation space, defined within an interior region of the shelter and surrounded by an inner enclosure, at a pressure less than the pressure of the environment of the interior region outside the inner enclosure.
 33. The method of claim 32 further comprising: defining a sealed wall space extending from any portion of the outer enclosure that can become exposed to the outer environment to the interior region; and maintaining the wall space at a pressure exceeding the pressure of the environment outside the shelter.
 34. The method of claim 33 further comprising: maintaining the desired pressure in the isolation space and the wall space by controllably supplying air to the isolation and wall spaces.
 35. The method of claim 34, wherein the supplied air is at least one of particulate filtered, charcoal filtered and decontaminated.
 36. The method of claim 33 further comprising the steps of: withdrawing air from the isolation space; supplying at a least a portion of the withdrawn air to at least one of the isolation space and the wall space; and at least one of particulate filtering, charcoal filtering and decontaminating the withdrawn air before the supplying step.
 37. The method of claim 36 further comprising the steps of: returning at least a portion of the withdrawn air to the outside environment; and at least one of particulate filtering, charcoal filtering and decontaminating the withdrawn air before the returning step.
 38. The method of claim 33 further comprising: receiving air from the outside environment; supplying at a least a portion of the supplied air to at least one of the isolation space and the wall space; and at least one of particulate filtering, charcoal filtering and decontaminating the received air before the supplying step.
 39. The method of claim 32 further comprising: providing an air lock passageway extending from the outside environment to a first location in the interior region.
 40. The method of claim 39, wherein the first location is within at least one of the isolation space, a sealed wall space extending from any portion of the outer enclosure that can become exposed to the outer environment to the interior region and a portion of the interior region disposed intermediate the isolation space and the wall space.
 41. The method of claim 32 further comprising: providing an air lock passageway extending through at least one structural element of the shelter, wherein the structural element is at least one of (i) an outer wall of the outer enclosure that can be exposed to the outside environment, (ii) an inner wall of the inner enclosure and (ii) a first structural element within the interior region and forming a part of the outer enclosure. 